ASTRONOMY: Evidence found for binary stars

Cinemagoers have known since Star Wars that planets can orbit around double, or "binary" stars: Luke Skywalker's home planet has a double sunset. Now astronomers have caught up. Today, in the science journal Nature they reveal the first evidence to back up the cinema vision, in the form of images of a dust disc around a binary star system more than 1,000 light years away.

Although planets or asteroids around other stars cannot be seen directly through telescopes, astronomers believe that the fine dust they generate could be revealed as a disc lit up by reflected light. However, only one other example of such a dust disc has been seen before, around the star Beta Pictoris.

The new finding is important because more than half the stars in our galaxy are members of binary or multiple systems. The binary star now thought to be a potential candidate for a planetary system is known only as BD+31x643. It is 1,075 light years from the Sun, in the constellation of Perseus.